MP Jeffrey Donaldson said at the weekend: "This is an option that we are actively considering at the moment and discussions are continuing."

Meanwhile, Sinn Fein's Gerry Kelly responded "we are very open to talk about that".

The News Letter understands that the DUP raised the idea with Alliance in a meeting several weeks ago, in an informal way.

Alliance, however, is believed to be of the view that it will not simply be used, as in the past, to get the Stormont Executive out of a hole, but will have its own list of demands, if it is to play its part in any such deal.

Alliance MLA Naomi Long said from their perspective "there has been no serious discussion with them about the issue".

"I mean this has been mentioned before – as far back as Peter Hain being Secretary of State – but there would need to be some serious engagement with us instead of Press speculation.

"As far as we are concerned we are there to do the job we were elected to do – to be the opposition.

"Westminster legislation specifically bars that particular circumstance because the post has to be held by either a unionist or a nationalist. The legislation would need to be changed to allow this to happen."

Despite continued deadlock on a range of issues – which has led to the cancellation of Executive meetings and a public blame game involving Peter Robinson and Gerry Adams – it is thought the DUP and Sinn Fein have made progress on policing and justice issues.

There is no date or exact timetable for devolving the powers, and the parties also remain at odds on matters such as the Maze stadium, rural planning and academic selection.

However, it has been speculated that a paper on policing and justice proposals - for the structures of any ministry, responsibilities etc - could be put to an Assembly committee soon.

Bringing in an Alliance minister would require special legislation at Westminster but Gordon Brown has given Sinn Fein and the DUP an assurance that this will not be a problem.

The two parties have also pressed the Prime Minister for additional funding for policing and to cover the costs of the public inquiries into disputed Troubles killings which come out of the justice budget.

But with no deals yet done and Gerry Adams last week accused the DUP of not taking talks seriously. Peter Robinson responded that Sinn Fein was blocking government business by vetoing the calling of Executive meetings.

SDLP deputy leader Alasdair McDonnell said Mr Adams had started a familiar blame game ahead of a Sinn Fein inspired crisis at the heart of government.

Dr McDonnell said the current deadlock was providing a vehicle for Mr Adams "in his ongoing quest for relevance" - given his lower profile and no role in the administration.

The SDLP man said: "We hear one day from a Sinn Fein junior minister (Gerry Kelly) that there is no crisis.

"The next Gerry Adams says there is a crisis. Which is it? Is it only a crisis when Gerry Adams says it is?

"The ordinary people of the North are getting fed up with Sinn Fein's ineffective, inefficient and incompetent way of government.

"It is clear they have not moved on from a party of protest to a party of government and are out of their depth."

Mr Adams' game playing was unacceptable, while ordinary people needed decision making at Stormont, he added.

"The SDLP believe there are powers within the Assembly's remit that can help. We must adopt a can do approach because doing nothing is simply not an option."